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Question

Millie takes a vitamin every day. What set of numbers should she use to say how many pills are left in the bottle?

Answer 1

Millie can use the set of non-negative integers (0, 1, 2, 3, ...) to indicate how many pills are left in the bottle. Non-negative integers are suitable because the number of pills cannot be negative; it can be zero (when the bottle is empty) or any positive integer (indicating the number of pills left).